Mitigating an inversion in broad acre spraying is of vital importance for spraying operations, in this post we'll briefly discuss as to why spraying during an inversion is a risk for any farm.One of the main causes for an inversion is when the temperature of the ground, is cooler than the air temperature. There are quite a few factors in causing an inversion to occur so a detailed analysis of local conditions day by day is pertinent. These inversions can cause driftable fines to be suspended and concentrated in a laminate air layer, which in turn can carry the fines into neighbouring fields causing damage.
How farmers can prevent inversions
To mitigate an inversion try to avoid spraying during the peak hours of inversion such as:
- Dusk and night
- Low wind speeds
- Light overnight cloud cover
- Dew which can indicate a cooler ground temperature
- Smoke stagnant in the air
- When temperatures are over 28°C etc
Always be sure to follow label instructions for any herbicide / pesticide that is being applied.
Using a tip that produces a larger droplet is also an effective way to minimise the risk that spraying in an inversion poses, as the nozzle produces a larger droplet and less driftable fines by volume.
This decreases the risk of driftable fines being caught in an inversion layer, but further to this, even with a larger droplet being produced, there will still be driftable fines, in this case, prudence and observance of the conditions that cause an inversion are still key for effective and safe spraying operations.
Fore more information regarding inversions and comprehensive studies on the topic, please visit the GRDC website.